# US 11,908,933 B2 · Designs for silicon carbide MOSFETs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,908,933 B2 - Document ID: US11908933B2 - Status: Granted - Kind: B2 - Application number: 17/686,571 - Filed: 2022-03-04 - Published: 2023-09-07 - Granted: 2024-02-20 - Earliest claimed: 2022-03-04 - Assignees: GeneSiC Semiconductor Inc. - Applicants: GeneSiC Semiconductor Inc. - Inventors: Siddarth Sundaresan; Ranbir Singh; Jaehoon Park - Web page: https://patentgrep.com/patent/US11908933B2 ## CPC - H10D 30/601: {having lightly-doped drain or source extensions, e.g. LDD IGFETs or DDD IGFETs (lightly doped source or drain extensions for TFTs H10D30/6715)} - H10D 12/031: {of IGBTs} - H10D 30/0291: {of vertical DMOS [VDMOS] FETs} - H10D 30/66: Vertical DMOS [VDMOS] FETs - H10D 62/155: {Shapes (cell layout of DMOS H10D62/127)} - H10D 62/393: {Body regions of DMOS transistors or IGBTs (cell layout of DMOS H10D62/127)} - H10D 62/8325: {Silicon carbide} - H10P 30/2042: {into crystalline silicon carbide} - H10P 30/21: {of electrically active species} - H10D 64/2527: {for vertical devices wherein the source or drain electrodes are recessed in semiconductor bodies} - H10D 64/62: Electrodes ohmically coupled to a semiconductor - H10P 30/218: {characterised by the implantation in a compound semiconductor of both electrically active and inactive species in the same semiconductor region to be doped n-type or p-type} - H10P 30/221: {characterised by the angle between the ion beam and the mask} - H10P 30/222: {characterised by the angle between the ion beam and the crystal planes or the main crystal surface (characterised by the angle between the ion beam and the mask H10P30/221)} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A metal-oxide-semiconductor field-effect transistor (MOSFET) device is described herein. The MOSFET device comprises a unit cell on a silicon carbide (SiC) substrate. The unit cell comprises: a source region; a well region; and a source attachment region. The source attachment region is in contact with the source region. The source attachment region is doped using first conductivity type ions. In an embodiment, the source attachment region is doped using second conductivity type ions. The source attachment region comprises a depth shallower than a depth of source region. In an embodiment, the source attachment region comprises a depth equal to a depth of the source region. The source attachment region comprises a doping concentration lower than a doping concentration of the source region. In an embodiment, the source attachment region comprises a doping concentration equal to a doping concentration of the source region. ## Claims ### Claim 1 A metal-oxide-semiconductor field-effect transistor (MOSFET) device comprising a unit cell on a silicon carbide (SiC) substrate, the unit cell comprising: a source region; a well region; a source attachment region; a gate oxide layer; and a gate metal layer, wherein the source attachment region is in direct contact with the source region, wherein the gate metal layer completely overlaps with the source attachment region, wherein the gate oxide layer extends beyond a lateral edge of the gate metal layer, and wherein the source attachment region comprises a doping concentration lower than a doping concentration of the source region. ### Claim 2 (depends on 1) The device of claim 1, wherein the source attachment region comprises a first conductivity type region. ### Claim 3 (depends on 1) The device of claim 1, wherein the source attachment region comprises a second conductivity type region. ### Claim 4 (depends on 1) The device of claim 1, wherein the source attachment region comprises a first depth shallower than a second depth of the source region. ### Claim 5 (depends on 1) The device of claim 1, wherein the source attachment region comprises a first depth equal to a second depth of the source region. ### Claim 6 (depends on 1) The device of claim 1, wherein the source attachment region comprises a first doping concentration equal to a second doping concentration of the source region. ### Claim 7 (depends on 1) The device of claim 1, wherein the device comprises a metal-oxide-semiconductor field-effect transistor (MOSFET) channel. ### Claim 8 (depends on 7) The device of claim 7, wherein the MOSFET channel extends from a first edge of the well region to a second edge of the source attachment region when the source attachment region comprises a first conductivity type region. ### Claim 9 (depends on 7) The device of claim 7, wherein the MOSFET channel comprises an extent that is equal to sum of the well region and the source attachment region when the source attachment region comprises a second conductivity type region. ### Claim 10 (depends on 1) The device of claim 1, wherein the device comprises a well contact region. ### Claim 11 (depends on 10) The device of claim 10, wherein the device comprises the well contact region at center of the unit cell. ### Claim 12 (depends on 10) The device of claim 10, wherein the device comprises the well contact region positioned at orthogonal location along a direction of the source region. ### Claim 13 (depends on 1) The device of claim 1, wherein the device comprises a trench region. ### Claim 14 (depends on 13) The device of claim 13, wherein the device comprises a well contact region located below the trench region. ### Claim 15 (depends on 13) The device of claim 13, wherein a third depth of the trench region is greater than a second depth of the source region. ### Claim 16 (depends on 1) The device of claim 1, wherein the device comprises a sinker region. ### Claim 17 (depends on 16) The device of claim 16, wherein the sinker region is located directly underneath the source region. ### Claim 18 (depends on 16) The device of claim 16, wherein the sinker region comprises a second conductivity type region. ### Claim 19 (depends on 1) The device of claim 1, wherein the source region is confined within the well region. ### Claim 20 (depends on 1) The device of claim 1, wherein the source attachment region is confined with the well region.